In recent years, great attention has been paid to asymmetric synthesis of chiral synthons that are used in developing modern drugs and agrochemicals. Chiral alcohols are one of the well-known synthons that can be obtained from corresponding prochiral ketones by asymmetric reduction.
However, numerous reduction reactions were carried out using different chemical and biocatalyst reductions (Corey. E. J., Helal, G. J. Angewantha Chern Int. Eng. (1998) 91 (1986) and Csuk, R. et al. Chern. Rev. (1991) 91 46; these reactions have some difficulties in attaining high chemical yield and optical purity under ecofriendly conditions. Asymmetric reduction by means of chemical methods involves use of expensive chiral reagents and environmental hazardous heavy metals. On the contrary use of biocatalyst microorganisms or plant cells for reduction of prochiral ketones yielding the corresponding optically active alcohols with excellent enantioselectivity are of present day interest.
The applicants now for the first time describe the novel methodology in oxido reduction of some of the pro-chiral functional keto functionalities e.g., acetophenones, cyclic ketones, β-keto esters, azidoketones and aliphatic ketones etc. along with their corresponding substituents using crude reductive enzymes isolated from tuberous roots carrot (D.corta) with yields ranging from 70–98%, with Ees' 92–98%, most preferably showing ‘S’ configurations. The final reduction products in all the cases leading to valuable chiral intermediates, which can be further used for total synthesis of various drugs and agrochemicals.